The US decision to supply weapons to Ukraine is dangerous as it will encourage Kiev to use force in eastern Ukraine, Russian officials say.
The US State Department said on Friday the United States would provide Ukraine with "enhanced defensive capabilities" as Kiev battles Russian-backed separatists in the eastern part of the country.
Supplies of any weapons now encourage those who support the conflict in Ukraine to use the "force scenario," Russia's RIA state news agency cited Deputy Foreign Minister Grigory Karasin as saying on Saturday.
Franz Klintsevich, a member of the upper house of parliament's security committee, said Kiev would consider arms supplies as support of its actions, Interfax news agency reported.
"Americans, in fact, directly push Ukrainian forces to war," Mr Klintsevich said.
After Moscow's annexation of Crimea in 2014, Ukraine and Russia are at loggerheads over a war in eastern Ukraine between pro-Russian separatists and Ukrainian government forces that has killed more than 10,000 people in three years.
Kiev accuses Moscow of sending troops and heavy weapons to the region, which Russia denies.
The Russian foreign ministry said the US decision once again undermines Minsk agreements, TASS state news agency reported on Saturday.
Minsk agreements intended to end the fighting in Ukraine were signed by Ukraine, Russia, Germany and France in the Belarussian capital in early 2015.
Meanwhile, German Chancellor Angela Merkel and French President Emmanuel Macron have urged the parties involved in an increase of ceasefire violations in eastern Ukraine to implement decisions they have already agreed upon.
Ukrainian officials, security monitors and Kiev's foreign backers had warned on Wednesday that Moscow's decision to withdraw from a Ukrainian-Russian ceasefire control group could worsen the fighting in eastern Ukraine.
Mr Macron and Ms Merkel said in their statement there was no alternative to an exclusively peaceful settlement and called for a return of the Russian officers to the Joint Centre for Control and Coordination. Russia had accused the Ukrainian side of obstructing their work and limiting access to the front line.
"In the light of the volatile security situation, they ask the sides for immediate and verifiable steps to remedy this situation," Mr Macron and Ms Merkel's statement said on Saturday.
"It is necessary to implement agreements on disengagement and the withdrawal of heavy weapons behind the agreed withdrawal lines, withdrawal of tanks, artillery and mortars to the agreed storage sites".
"Other aspects of the Minsk agreements, like the withdrawal of foreign armed formations or the return of control over the Russian-Ukrainian border need to addressed seriously as well."
Fighting in eastern Ukraine has escalated to the worst level in months, officials monitoring the conflict said on Tuesday.